In vitro study of the variable effects of proton pump inhibitors on voriconazole

Notable drug-drug interaction between omeprazole and voriconazole in CYP2C19 *1 and *2 (rs4244285, 681G>A) alleles in vitro

The drug-drug interaction (DDI) and CYP2C19 genetic variation can lead to a high blood concentration of voriconazole. CYP2C19 is a highly genetically polymorphic enzyme, and CYP2C19*2 is more frequent among Asians associated with reduced metabolism of drugs. Clinical study found that co-administration with omeprazole significantly increased voriconazole concentrations and there was an additive effect in CYP2C19*2 allele.CYP2C19 rs4244285 (681G>A) is the key polymorphism of CYP2C19*2 allele. This study aims to describe the in vitro effects of omeprazole on CYP2C19*1 and *2 (681G>A), and determine how CYP2C19 polymorphisms influence the DDI between omeprazole and voriconazole.Using the lentiviral expression system, we successfully generated HepG2-derived cell lines stably expressing CYP2C19*1 and *2 (681G>A). The results showed that the CYP2C19 mRNA level, protein level, and enzymatic activity were lower in HepG2-CYP2C19*2 (681G>A) than HepG2-CYP2C19*1 cells. Our study also showed that the inhibition rates of omeprazole on voriconazole had no significantly differences between CYP2C19*1 and *2 (681G>A). But the IC50 of omeprazole on CYP2C19*1 slightly lower than CYP2C19*2 (681G>A).Moreover, omeprazole inhibited CYP2C19 protein level in cells carrying CYP2C19*1 and CYP2C19*2 (681G>A). Our study demonstrated that omeprazole could inhibit voriconazole metabolism in both CYP2C19*1 and CYP2C19*2 (681G>A).

The Fragile Patient: Considerations in the Management of Invasive Mould Infections (IMIs) in India

Invasive mould infections (IMIs), which are mostly caused by Aspergillus spp. and Mucormycetes, are opportunistic infections that impose a substantial threat to patients who are considered to be 'fragile'. There is no fixed definition for fragile patients; however, patients with cancer or acquired immunodeficiency syndrome (AIDS), patients who have undergone organ transplants, and patients being treated in the intensive care units (ICUs) were considered fragile. Management of IMIs in fragile patients is challenging, owing to their compromised immune status. The diagnostic challenges associated with IMIs due to insufficient sensitivity and specificity of the current diagnostic tests lead to delayed treatment. A widening demographic of at-risk patients and a broadening spectrum of pathogenic fungi have added to the challenges to ascertain a definite diagnosis. A recent surge of mucormycosis associated with SARS-CoV-2 infections and the resultant steroid usage has been reported. Liposomal amphotericin B (L-AmB) is the mainstay for treating mucormycosis while voriconazole has displaced amphotericin B as the mainstay for treating Aspergillus infection due to its better response, improved survival, and fewer severe side effects. The selection of antifungal treatment has to be subjected to more scrutiny in fragile patients owing to their comorbidities, organ impairment, and multiple ongoing treatment modalities. Isavuconazole has been documented to have a better safety profile, stable pharmacokinetics, fewer drug-drug interactions, and a broad spectrum of coverage. Isavuconazole has thus found its place in the recommendations and can be considered a suitable option for treating fragile patients with IMIs. In this review, the authors have critically appraised the challenges in ascertaining an accurate diagnosis and current management considerations and suggested an evidence-based approach to managing IMIs in fragile patients.

Evaluation of Pharmacokinetics and Safety With Bioequivalence of Voriconazole Injection of 2 Formulations in Chinese Healthy Volunteers: Bioequivalence Study

Voriconazole is a first-line medicine for treating invasive aspergillosis. We aimed to evaluate the bioequivalence (BE) of voriconazole injection in Chinese healthy volunteers (HVs). In this single-center, randomized, single-dose, 2-cycle, fasting-dose BE study, HVs (n = 24) were 1:1 divided into 2 groups (test [T]-reference [R] and R-T) and received 6 mg/kg of voriconazole intravenously with a 7-day washout. The plasma was collected for up to 72 hours at the time point after dosing on day 1/day 8. The plasma concentration of voriconazole was measured by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were ascertained on the basis of a noncompartmental model. In the BE study, the geometric mean ratios of the maximum concentration, area under the concentration-time curve from time 0 to the last measurable plasma concentration, and area under the concentration-time curve from time 0 to infinity were 101.1%, 105.6%, and 105.5%, respectively, and the 90%CI fell within 80%-125%. Adverse events were observed in 26.1% of subjects in the T formulation stage and 17.4% in the R formulation stage. Under the BE study, voriconazole values from T and R formulations were bioequivalent.

Population pharmacokinetics of voriconazole and initial dosage optimization in patients with talaromycosis

The high variability and unpredictability of the plasma concentration of voriconazole (VRC) pose a major challenge for clinical administration. The aim of this study was to develop a population pharmacokinetics (PPK) model of VRC and identify the factors influencing VRC PPK in patients with talaromycosis. Medical records and VRC medication history of patients with talaromycosis who were treated with VRC as initial therapy were collected. A total of 233 blood samples from 69 patients were included in the study. A PPK model was developed using the nonlinear mixed-effects models (NONMEM). Monte Carlo simulation was applied to optimize the initial dosage regimens with a therapeutic range of 1.0–5.5 mg/L as the target plasma trough concentration. A one-compartment model with first-order absorption and elimination adequately described the data. The typical voriconazole clearance was 4.34 L/h, the volume of distribution was 97.4 L, the absorption rate constant was set at 1.1 h^-1, and the bioavailability was 95.1%. Clearance was found to be significantly associated with C-reactive protein (CRP). CYP2C19 polymorphisms had no effect on voriconazole pharmacokinetic parameters. ‏Monte Carlo simulation based on CRP levels showed that a loading dose of 250 mg/12 h and a maintenance dose of 100 mg/12 h are recommended for patients with CRP ≤ 96 mg/L, whereas a loading dose of 200 mg/12 h and a maintenance dose of 75 mg/12 h are recommended for patients with CRP > 96 mg/L. The average probability of target attainment of the optimal dosage regimen in CRP ≤ 96 mg/L and CRP > 96 mg/L groups were 61.3% and 13.6% higher than with empirical medication, and the proportion of C_min > 5.5 mg/L decreased by 28.9%. In conclusion, the VRC PPK model for talaromycosis patients shows good robustness and predictive performance, which can provide a reference for the clinical individualization of VRC. Adjusting initial dosage regimens based on CRP may promote the rational use of VRC.

The Effects of Intravitreal Administration of Antifungal Drugs on the Structure and Mechanical Properties Peripheral Blood Erythrocyte Surface in Rabbits

Background: Fungal infections can pose great threat to sight. Immediate treatment is usually required; antifungal agents are widely accepted and are effective in most cases. The present experimental study aims to investigate the probable effects of intravitreal injection of antifungal agents on the structure and mechanical properties of the surface of peripheral blood erythrocytes. Methods: Nine albino New Zealand white rabbits, aged five months old, were chosen for the experiment. Solutions of micafungin, voriconazole, or balanced salt solution (BSS) were injected into the midvitreous. Animals were divided into two experimental groups and one control group. Blood sampling from an intravenous (IV) line was performed after 10 days from the last IV injection. An atomic force microscope (AFM) was used to study the structural and mechanical properties of cell surfaces. Results: The analysis results showed that the parameters of the cytoskeleton’s spatial organization changed insignificantly with the antifungal drug treatment. Conclusions: Our findings suggest that locally administered antifungal drugs can cause significant changes to the structure and frictional properties of the erythrocyte surface. These effects occur in the long-term period after administration of the drugs and represent a potential possibility for violation of blood supply to tissues, and the further development of negative side effects.

Co-Administration with Voriconazole Doubles the Exposure of Ruxolitinib in Patients with Hematological Malignancies

BACKGROUND

Ruxolitinib is newly approved for glucocorticoid-refractory acute graft-versus-host disease (GVHD) in patients undergoing allo-geneic hematopoietic stem-cell transplantation (allo-HSCT), and voriconazole is commonly used in allo-HSCT recipients for the prophylaxis or treatment of invasive fungal infections (IFIs). Drug-drug interaction (DDI) may occur between them because their metabolic pathways overlap and can be inhibited by voriconazole, including cytochrome P450 (CYP) isozymes 3A4 and 2C9.

OBJECTIVE

In the present study, we aimed to investigate the DDI between ruxolitinib and voriconazole in patients with hematological malignancies.

METHODS

A total of 12 patients with hematologic malignancies were enrolled in this single-arm, single-center, Phase I/II, fixed sequence self-control study. All subjects received 5 mg ruxolitinib alone, followed by the co-administration of ruxolitinib and voriconazole. The plasma concentrations of the two drugs were determined by two well-validated high-performance liquid chromatography-tandem mass spectrometry methods. Phoenix WinNonlin software was used to compare the differences in maximum plasma concentration (Cmax), time to Cmax (Tmax), terminal elimination half-life (T1/2), and apparent plasma clearance (CL/F), as well as area under the curve from time zero to last (AUClast) and AUC from time zero to infinity (AUCinf) between the two periods.

RESULTS

After pre-treatment with voriconazole, no significant change existed in Tmax, while Cmax, T1/2, AUClast, and AUCinf of ruxolitinib were significantly increased by 50.4%, 81.3%, 110.1%, and 118.3%, respectively, and CL/F was significantly decreased to 43.6% compared with patients receiving ruxolitinib alone.

CONCLUSION

Our findings confirmed a moderate inhibitory DDI between ruxolitinib and voriconazole as voriconazole decreased the elimination and increased the exposure of ruxolitinib in patients with hematologic malignancies. We recommended a dose reduction regimen when voriconazole and ruxolitinib were coadministered. Drug monitoring might help determine the ruxolitinib treatment concentration for aGVHD patients, improve efficacy, and reduce toxicity.

Analysis of Combined Effect of CYP2C19 Genetic Polymorphism and Proton Pump Inhibitors Coadministration on Trough Concentration of Voriconazole

Purpose

To analyze the combined effect of CYP2C19 genetic polymorphism and PPIs coadministration on voriconazole trough concentration (VCZ-C_trough) in Chinese patients with hematological disorders.

Patients and Methods

A prospective observational study involved 250 plasma samples from 114 adult patients receiving voriconazole with or without PPIs were analyzed. Demographics and clinical characteristics were obtained from patient’s records. A validated LC-MS/MS was used to quantify the plasma VCZ-C_trough. Genotyping for CYP2C19*2 and CYP2C19*3 variant alleles was performed by PCR-RFLP followed by DNA sequencing. The combined total score (from 2 to 5) was calculated for each patient. The higher the score, the lesser the metabolism of the patient.

Findings

Fifty percent of patients administered with voriconazole were coadministered with PPIs, predominantly omeprazole or esomeprazole. Patients exhibiting CYP2C19 poor metabolizer phenotype showed a significantly higher median VCZ-C_trough, (4.31µg/mL [IQR, 1.64µg/mL–7.36µg/mL]) than patients with normal metabolizer (1.38µg/mL, [IQR, 0.79µg/mL–2.14µg/mL], p < 0.0001). Similarly, patients co-administration with PPIs had higher median VCZ-C_trough (2.86µg/mL [IQR 1.33µg/mL–4.66µg/mL]), than PPIs non-users (1.71µg/mL, [IQR, 0.86µg/mL–3.48µg/mL], p = 0.001). However, we noted that the median VCZ-C_trough for each factor was ranging within the normal recommended therapeutic range in the Chinese population (0.5µg/mL–5µg/mL). But when the two factors were combined, the median VCZ-C_trough was steadily increasing as the metabolic capacity (reflected by combined total score) was increasing. Importantly, the median VCZ-C_trough in PM/PPIs user (total score 5) was significantly elevated to supra-therapeutic levels compared to NM/PPI non-user group (total score 2) (5.83µg/mL [IQR, 2.19µg/mL–9.51µg/mL] versus 1.13µg/mL [IQR, 0.67µg/mL–1.82µg/mL]), respectively, P < 0.0001. Furthermore, we observed that the elevation of median VCZ-C_trough to supra-therapeutic levels was largely contributed by omeprazole or esomeprazole compared to lansoprazole or pantoprazole.

Conclusion

Coadministration with PPIs significantly increased voriconazole trough concentrations and there was an additive effect in CYP2C19 PMs, who were most likely to have supra-therapeutic levels.

Effects of Voriconazole on the Pharmacokinetics of Vonoprazan in Rats

Purpose

The purpose of this study was to examine the effects of voriconazole on the pharmacokinetics of vonoprazan.

Methods

Fifteen Sprague-Dawley rats were randomly divided into three groups: five rats in each group, including control group, single-dose group (a single dose of 30 mg/kg of voriconazole), and multiple-dose group (multiple doses of 30 mg/(kg•day) per dose of voriconazole). Each group of rats was given an oral dose of 10 mg/kg vonoprazan 30 min after the administration of voriconazole or vehicle. After the oral administration of vonoprazan, 50 µL of blood was collected into 1.5-mL heparinized tubes via the caudal vein. The concentration of vonoprazan in plasma was quantified by ultra-performance liquid chromatography/tandem mass spectrometry. Both in vitro effects of voriconazole on vonoprazan and the mechanism of the observed inhibition were studied in rat liver microsomes.

Results

When orally administered, voriconazole increased the area under the plasma concentration-time curve (AUC), prolonged the elimination half-life (t_1/2), and decreased the clearance (CL) of vonoprazan; there was no significant difference between the single-dose and multiple-dose groups. Voriconazole inhibited the metabolism of vonoprazan at an IC50 of 2.93 μM and showed mixed inhibition. The results of the in vivo experiments were consistent with those of the in vitro experiments.

Conclusion

Our findings provide the evidence of drug-drug interactions between voriconazole and vonoprazan that could occur with pre-administration of voriconazole. Thus, clinicians should pay attention to the resulting changes in pharmacokinetic parameters and accordingly, adjust the dose of vonoprazan in clinical settings.

Pharmacological Effects and Toxicogenetic Impacts of Omeprazole: Genomic Instability and Cancer

Omeprazole (OME) is commonly used to treat gastrointestinal disorders. However, long-term use of OME can increase the risk of gastric cancer. We aimed to characterize the pharmacological effects of OME and to correlate its adverse effects and toxicogenetic risks to the genomic instability mechanisms and cancer-based on database reports. Thus, a search (till Aug 2019) was made in the PubMed, Scopus, and ScienceDirect with relevant keywords. Based on the study objective, we included 80 clinical reports, forty-six in vitro, and 76 in vivo studies. While controversial, the findings suggest that long-term use of OME (5 to 40 mg/kg) can induce genomic instability. On the other hand, OME-mediated protective effects are well reported and related to proton pump blockade and anti-inflammatory activity through an increase in gastric flow, anti-inflammatory markers (COX-2 and interleukins) and antiapoptotic markers (caspases and BCL-2), glycoprotein expression, and neutrophil infiltration reduction. The reported adverse and toxic effects, especially in clinical studies, were atrophic gastritis, cobalamin deficiencies, homeostasis disorders, polyp development, hepatotoxicity, cytotoxicity, and genotoxicity. This study highlights that OME may induce genomic instability and increase the risk of certain types of cancer. Therefore, adequate precautions should be taken, especially in its long-term therapeutic strategies and self-medication practices.

A multicentre prospective study evaluating the impact of proton-pump inhibitors omeprazole and pantoprazole on voriconazole plasma concentrations

Voriconazole is an antifungal metabolised by CYP2C19 enzyme, which can be inhibited by proton-pump inhibitors (PPIs). A prospective observational study was carried out to determine the influence of PPIs on voriconazole pharmacokinetic. The 78 patients included were divided into 4 groups: omeprazole (n = 32), pantoprazole (n = 25), esomeprazole (n = 3) and no PPI (n = 18). Patients with no PPI had no significant difference in plasma voriconazole concentration when compared with those with PPI (2.63 ± 2.13 μg/mL [95% confidence interval {CI} 1.57-3.69] vs 2.11 ± 1.73 μg/mL [95%CI 1.67-2.55], P > .05). However, voriconazole plasma concentration was significantly lower in patients treated with pantoprazole vs those treated with omeprazole (1.44 ± 1.22 μg/mL [95%CI 0.94-1.94) vs 2.67 ± 1.88 μg/mL [95%CI 2.02-3.32], P = .013) suggesting a greater CYP2C19 enzyme inhibitory effect of omeprazole. This study demonstrates the greater CYP inhibition capacity of omeprazole and should be helpful for the choice of PPIs for patients treated with voriconazole.

Recent insight on improving the iron chelation efficacy of deferasirox by adjuvant therapy in transfusion dependent beta thalassemia children with sluggish response

Background: Deferasirox is the first line of treatment in iron overload. In spite of the many studies concerning the efficacy of deferasirox, some patients remain unresponsive to deferasirox.Methods: One hundred and sixty patients were enrolled in stratified-randomized controlled study. Patients were randomly divided into four regimens, group I (n = 40) received 30 mg/kg deferasirox, group II (n = 40) received 20 mg omeprazole and 30 mg/kg deferasirox, group III (n = 40) received 400 mg vitamin E and 30 mg/kg deferasirox and group IV (n = 40) received 420 mg silymarin and 30 mg/kg deferasirox. Blood specimens were collected from each patient for up to 24 h, and then plasma deferasirox concentrations were inspected.Results: Silymarin, Vitamin E, and omeprazole significantly increased the peak plasma concentration of deferasirox (P < 0.001) by 27.9, 14.9 and 2.4 fold, respectively, as compared to deferasirox alone. The bioavailability of deferasirox was improved up to 3.03, 3.57, and 4.98-fold, respectively, following administration of omeprazole, vitamin E, and silymarin compared to deferasirox alone.Conclusion: Silymarin, vitamin E, and omeprazole represent promising adjuvant therapy to improve the chelation efficacy of deferasirox that might also be further applied to enhance the pharmacokinetics of deferasirox to overcome the lack of response.

Novel insights into the complex pharmacokinetics of voriconazole: a review of its metabolism

Voriconazole, a second-generation triazole frequently used for the prophylaxis and treatment of invasive fungal infections, undergoes complex metabolism mainly involving various (polymorphic) cytochrome P450 enzymes in humans. Although high inter- and intraindividual variability in voriconazole pharmacokinetics have been observed and the therapeutic range for this compound is relatively narrow, the metabolism of voriconazole has not been fully elucidated yet. The available literature data investigating the multiple different pathways and metabolites are extremely unbalanced and thus the absolute or relative contribution of the different pathways and enzymes involved in the metabolism of voriconazole remains uncertain. Furthermore, other factors such as nonlinear pharmacokinetics caused by auto-inhibition or -induction and polymorphisms of the metabolizing enzymes hinder safe and effective voriconazole dosing in clinical practice and have not yet been studied sufficiently. This review aimed at amalgamating the available literature on the pharmacokinetics of voriconazole in vitro and in vivo, with a special focus on metabolism in adults and children, in order to congregate an overall landscape of the current body of knowledge and identify knowledge gaps, opening the way towards further research in order to foster the understanding, towards better therapeutic dosing decisions.

Risk factors associated with insufficient and potentially toxic voriconazole plasma concentrations: an observational study

The aim of this study was to identify potential factors associated with insufficient/toxic voriconazole trough concentrations (VTCs) in patients in order to screen the high-risk population. A total of 119 VTCs were obtained from 67 patients. Multivariate regression analysis suggested that insufficient VTCs (<1.0 mg/L) were significantly associated with younger age and underlying hematological malignancy, and toxic VTCs (>5.5 mg/L) were significantly associated with lower serum albumin (ALB) level. Receiver operating characteristic curve analysis indicated that patients whose age < 47 years were the high-risk population of insufficient VTCs, and patients whose ALB <27 g/L were the high-risk population of toxic VTCs. Younger age and underlying hematological malignancy were significant predictors of insufficient VTCs, and lower ALB level was found to be a significant predictor of toxic VTCs. Therefore, we recommend to increase the monitoring on these high-risk population to avoid treatment failure and to prevent toxic adverse events.

Therapeutic Drug Monitoring of Voriconazole in Children from a Tertiary Care Center in China

Voriconazole is a broad-spectrum triazole antifungal and the first-line treatment for invasive aspergillosis (IA). The aim of this research was to study the dose adjustments of voriconazole as well as the affecting factors influencing voriconazole trough concentrations in Asian children to optimize its daily administration. Clinical data were analyzed of inpatients 2 to 14 years old who were subjected to voriconazole trough concentration monitoring from 1 June 2015 to 1 December 2017. A total of 138 voriconazole trough concentrations from 42 pediatric patients were included. Voriconazole trough concentrations at steady state ranged from 0.02 to 9.35 mg/liter, with high inter- and intraindividual variability. Only 50.0% of children achieved the target range (1.0 to 5.5 mg/liter) at initial dosing, while 35.7% of children were subtherapeutic, and 14.3% of children were supratherapeutic at initial dosing. There was no correlation between initial trough concentrations and initial dosing. A total of 28.6% of children (12/42) received an adjusted dose according to trough concentrations. Children <6, 6 to 12, and >12 years old required a median oral maintenance dose to achieve the target range of 11.1, 7.2, and 5.3 mg/kg twice daily, respectively (P = 0.043). The average doses required to achieved the target range were 7.7 mg/kg and 5.6 mg/kg, respectively, and were lower than the recommended dosage (P = 0.033 and 0.003, respectively). Affecting factors such as administration routes and coadministration with proton pump inhibitors (PPIs) explained 55.3% of the variability in voriconazole exposure. Therapeutic drug monitoring (TDM) of voriconazole could help to individualize antifungal therapy for children and provide guidelines for TDM and dosing optimization in Asian children.

Reduced Effectiveness of Interruptive Drug-Drug Interaction Alerts after Conversion to a Commercial Electronic Health Record

BACKGROUND

Drug-drug interaction (DDI) alerts in electronic health records (EHRs) can help prevent adverse drug events, but such alerts are frequently overridden, raising concerns about their clinical usefulness and contribution to alert fatigue.

OBJECTIVE

To study the effect of conversion to a commercial EHR on DDI alert and acceptance rates.

DESIGN

Two before-and-after studies.

PARTICIPANTS

3277 clinicians who received a DDI alert in the outpatient setting.

INTERVENTION

Introduction of a new, commercial EHR and subsequent adjustment of DDI alerting criteria.

MAIN MEASURES

Alert burden and proportion of alerts accepted.

KEY RESULTS

Overall interruptive DDI alert burden increased by a factor of 6 from the legacy EHR to the commercial EHR. The acceptance rate for the most severe alerts fell from 100 to 8.4%, and from 29.3 to 7.5% for medium severity alerts (P < 0.001). After disabling the least severe alerts, total DDI alert burden fell by 50.5%, and acceptance of Tier 1 alerts rose from 9.1 to 12.7% (P < 0.01).

CONCLUSIONS

Changing from a highly tailored DDI alerting system to a more general one as part of an EHR conversion decreased acceptance of DDI alerts and increased alert burden on users. The decrease in acceptance rates cannot be fully explained by differences in the clinical knowledge base, nor can it be fully explained by alert fatigue associated with increased alert burden. Instead, workflow factors probably predominate, including timing of alerts in the prescribing process, lack of differentiation of more and less severe alerts, and features of how users interact with alerts.

The impact of proton pump inhibitors on the pharmacokinetics of voriconazole in vitro and in vivo

Voriconazole (VRC) and proton pump inhibitors (PPIs) have similar metabolic pathways. The objectives of the study are to evaluate the impact of PPIs on the pharmacokinetics of VRC. Human liver microsomes model was applied to assess the inhibitory effects of PPIs on the metabolism of VRC in vitro. A retrospective study was also carried out to explore the relationship between the plasma VRC trough concentrations and PPIs uses. Patients were divided into six groups: control (n = 166), lansoprazole (LAN, n = 38), esomeprazole (ESO, n = 19), omeprazole (OME, n = 45), pantoprazole (PAN, n = 43), and ilaprazole (ILA, n = 38) groups. All five PPIs showed concentration-dependent inhibitory effects on the VRC metabolism in human liver microsomes, among which LAN, OME and ESO were three of the most potent inhibitors. Consistently, co-administered with LAN, OME and ESO significantly increased the plasma VRC trough levels (p <  0.05), whereas there was no significant association between VRC concentrations and PAN or ILA use. Interestingly, patients in the PPIs groups were more likely to reach the therapeutic VRC range of 1-5.5 μg/mL in steady state when compared with control patients (75-81% VS 69%). In conclusion, although all PPIs showed inhibitory effects on the VRC metabolism in vitro, only LAN, OME and ESO significantly increased VRC plasma concentrations. This study should be helpful for choice of the type of PPIs for patients administered with VRC.

Determination of voriconazole and co-administered drugs in plasma of pediatric cancer patients using UPLC-MS/MS: A key step towards personalized therapeutics

Untreated invasive aspergillosis results in high mortality rate in pediatric cancer patients. Voriconazole (VORI), the first line of treatment, requires strict dose monitoring because of its narrow therapeutic index and individual variation in plasma concentration levels. Commonly co-administered drugs; either Esomeprazole (ESO) or Ondansetron (OND) have reported drug-drug interaction with VORI that should adversely alter therapeutic outcomes of the latter. Although VORI, ESO and OND are co-administered to pediatric cancer patients, the combined effect of ESO and OND on the plasma concentration levels of VORI has not been fully explored. In this study, an accurate, reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed and validated for simultaneous determination of VORI, ESO, and OND in ultra-low sample volumes (25 μL) of plasma of pediatric cancer patients. Based on the physicochemical properties of the studied drugs and internal standard, liquid-liquid extraction was successfully adopted with methyl t-butyl ether. Consistent and reproducible recovery of the three drugs and the internal standard were calculated using plasma and matrix matched samples (RE% > 72.97%, RSD < 8.29%). Chromatographic separation was carried out using UPLC with C18 column and a mobile phase of acetonitrile:water:methanol (70:25:5 V/V/V) at 0.3 mL/min. Mass spectrometric determination at positive electrospray ionization in the MRM mode was employed. The analysis was achieved within 4 min over a linear concentration range of 1.00-200.00 ng/mL for the three drugs. The assay validity was assessed as per the Food and Drug Administration guidelines for bioanalytical method validation, and satisfactory results were obtained. The accuracy and precision were within the acceptable limits for the three drugs in both quality control and incurred plasma samples. Matrix effect and process efficiency were investigated in neat solvent, post-extraction matrix, and plasma. Correlation of the plasma concentration levels of the three drugs revealed differences from the reported drug-drug interactions. This confirmed the need for simultaneous determination of VORI and co-administered drugs in order to achieve optimal therapeutic outcomes. To achieve this, analysis results of this study, genetic polymorphisms in CYP2C19 and clinical data will be used to establish one model incorporating all possible factors that might lead to variation in therapeutic outcomes.

Pharmacogenetic of voriconazole antifungal agent in pediatric patients

AIM

We explored the role of SNPs within the SLCO1B3, SLCO1B1, SLC22A6, ABCB1, ABCG2, SLCO3A1, CYP2C19, ABCC2, SLC22A1, ABCB11 and NR1I2 genes on voriconazole pharmacokinetics.

PATIENTS & METHODS

233 pediatric patients were enrolled. Drug plasma C_trough was measured by a HPLC-MS method. Allelic discrimination was performed by qualitative real-time PCR.

RESULTS

SLCO1B3 rs4149117 c.334 GT/TT (p = 0.046), ABCG2 rs13120400 c.1194 + 928 CC (p = 0.029) and ABCC2 rs717620 c.-24 GA/AA (p = 0.025) genotype groups significantly influenced C_trough. ethnicity (p = 0.042), sex (p = 0.033), SLCO1B3 rs4149117 c.334 GT/TT (p = 0.041) and ABCB1 rs1045642 c.3435 TT (p = 0.016) have been retained in linear regression model as voriconazole predictor factors.

CONCLUSION

Understanding how some gene polymorphisms affect the voriconazole pharmacokinetic is essential to optimally dose this agent.

Drug-drug interactions between triazole antifungal agents used to treat invasive aspergillosis and immunosuppressants metabolized by cytochrome P450 3A4

Patients undergoing treatment with immunosuppressant drugs following solid organ or hematopoietic stem cell transplantation are at particular risk for development of serious infections such as invasive aspergillosis. Four triazole antifungal drugs, voriconazole, posaconazole, itraconazole, and isavuconazole, are approved to treat invasive aspergillosis either as first- or second-line therapy. All of these agents are inhibitors of cytochrome P450 3A4, which plays a key role in metabolizing immunosuppressant drugs such as cyclosporine, tacrolimus, and sirolimus. Thus, co-administration of a triazole antifungal drug with these immunosuppressant drugs can potentially increase plasma concentrations of the immunosuppressant drugs, thereby resulting in toxicity, or upon discontinuation, inadvertently decrease the respective concentrations with increased risk of rejection or graft-versus-host disease. In this article, we review the evidence for the extent of inhibition of cytochrome P450 3A4 by each of these triazole antifungal drugs and assess their effects on cyclosporine, tacrolimus, and sirolimus. We also consider other factors affecting interactions of these two classes of drugs. Finally, we examine recommendations and strategies to evaluate and address those potential drug-drug interactions in these patients.

Therapeutic drug monitoring of voriconazole for treatment and prophylaxis of invasive fungal infection in children

Voriconazole therapeutic drug monitoring is not consistently recommended due to its high interpatient and intrapatient variability. Here, we aimed to describe our experience with voriconazole for treatment and prophylaxis of invasive fungal infections in paediatric patients. A fully validated high-performance liquid chromatography-mass spectrometry method was used to quantify voriconazole concentration in plasma, at the end of dosing interval. A high interindividual variability was shown. We enrolled 237 children, 83 receiving intravenous and 154 oral voriconazole. A positive correlation between drug dose and drug plasma exposure was observed. Considering intravenous route, patients with higher serum creatinine had higher voriconazole concentrations; a positive correlation was found among drug exposure and age. Sex significantly influenced drug levels: males had higher median drug concentrations than females (P < 0.001). Close voriconazole pharmacokinetics monitoring should help individualize antifungal therapy for children.

Gastroesophageal Reflux Disease and Pulmonary Diseases Associated with Aspergillosis: Is There a Connection?

INTRODUCTION

We studied the relationship between GORD and allergic bronchopulmonary aspergillosis (ABPA), chronic pulmonary aspergillosis (CPA), or Aspergillus bronchitis.

BACKGROUND

Gastroesophageal reflux disease (GORD) is well known to initiate or exacerbate pulmonary inflammatory conditions, inducing bronchial asthma and chronic obstructive lung disease.

METHODS

We reviewed four patients referred with elevated Aspergillus serology markers and marked pulmonary symptoms for ABPA, CPA, and Aspergillus bronchitis, and discussed the underlying pathophysiological relationship with GORD. Data were collected retrospectively from medical records included age, gender, predisposing factors for ABPA, chronic pulmonary aspergillosis, or Aspergillus bronchitis; presence of nocturnal reflux, nausea, epigastric pain, Medical Research Council dyspnea scale score, pH manometry data, endoscopic results (ulcers, Barrett's esophagus), treatment of GORD [proton-pump inhibitors (PPIs), surgical operation]; history of smoking, alcohol consumption; concomitant COPD; serological markers (anti-Aspergillus IgG, anti-Aspergillus IgE), and antifungal treatment.

RESULTS

Four patients with GORD were studied; following PPIs administration two achieved clinical improvement. One had ABPA, one CPA, and two had Aspergillus bronchitis; median age was 57 years [range 39-71]; males-to-females ratio was 1:3. Serological markers for aspergillosis were: median total IgE antibodies 573 KIU/L [range 13.1-850], median Aspergillus IgE-specific antibodies 1.2 kAU/L [range <0.4-24.7], and median Aspergillus IgG titers 71 mg/L [range 20-119]. Aspergillus fumigatus grew in one sputum sample.

CONCLUSION

Clinicians caring for patients with gastroesophageal reflux disease presenting with elevated Aspergillus IgG or IgE antibodies should maintain a high index of suspicion for this association and proceed to appropriate evaluations, including laryngoscopy and endoscopy, initiating specific PPI-directed therapy when indicated.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Influence of different proton pump inhibitors on the pharmacokinetics of voriconazole

This study aimed to determine the influence of proton pump inhibitors (PPIs) on the pharmacokinetics of voriconazole and to characterise potential drug-drug interactions (DDIs) between voriconazole and various PPIs (omeprazole, esomeprazole, lansoprazole and rabeprazole). Using adjusted physicochemical data and the pharmacokinetic (PK) parameters of voriconazole and PPIs, physiologically based pharmacokinetic (PBPK) models were built and were verified in healthy subjects using GastroPlus^TM to predict the plasma concentration-time profiles of voriconazole and PPIs. These models were then used to assess potential DDIs for voriconazole when administered with PPIs. The results indicated the PBPK model-simulated plasma concentration-time profiles of both voriconazole and PPIs were consistent with the observed profiles. In addition, the DDI simulations suggested that the PK values of voriconazole increased to various degrees when combined with several PPIs. The area under the plasma concentration-time curve for the time of the simulation (AUC_0-t) of voriconazole was increased by 39%, 18%, 12% and 1% when co-administered with omeprazole, esomeprazole, lansoprazole and rabeprazole, respectively. Omeprazole was the most potent CYP2C19 inhibitor tested, whereas rabeprazole had no influence on voriconazole (omeprazole > esomeprazole > lansoprazole > rabeprazole). However, in consideration of the therapeutic concentration range, dosage adjustment of voriconazole is unnecessary regardless of which PPI was co-administered.

Different effects of lansoprazole and rabeprazole on the plasma voriconazole trough levels in allogeneic hematopoietic cell transplant recipients

Voriconazole (VRC) is widely used as prophylaxis and in the treatment of invasive fungal disease (IFD) after allogeneic hematopoietic cell transplantation (HCT). We retrospectively examined the results of VRC therapeutic drug monitoring (TDM) in allogeneic HCT recipients. A total of 474 samples were obtained from 59 adult patients who received VRC during the first 100 days following HCT between 2009 and 2014 in our institute. Seventeen patients received VRC for prophylaxis of IFD, and 42 received VRC for the empirical or preemptive therapy for IFD. A total of 299 samples (63 %) were obtained during the administration of the intravenous form of VRC. The median VRC daily dose based on the actual body weight was 6.68 mg/kg/day (range, 1.92-10.41 mg/kg/day). The median VRC trough level was 0.99 mg/l (range, <0.09-5.45 mg/l). The multivariate analysis using a logistic regression model demonstrated significantly higher VRC trough levels (≥1.0 mg/l) in males (P < 0.001), empirical or preemptive therapy (P = 0.002), VRC daily dose based on the actual body weight ≥7 mg/kg/day (P < 0.001), and concomitant use of lansoprazole as compared to rabeprazole (P < 0.001). The concomitant use of calcineurin inhibitors and corticosteroids had no effects on VRC trough levels in multivariate analysis. These data suggest that lansoprazole and rabeprazole have different effects on the plasma VRC trough levels in the allogeneic HCT recipients.

Antagonism of Fluconazole and a Proton Pump Inhibitor against Candida albicans

Hospitalized ill patients, at risk for invasive candidiasis, often receive multiple medications, including proton pump inhibitors (PPIs). The antifungal fluconazole perturbs the vacuolar proton ATPase. The PPI omeprazole antagonized Candida albicans growth inhibition by fluconazole. A C. albicans codon-adapted pHluorin, Ca.pHluorin, was generated to measure cytosolic pH. The fungal cytosol was acidified by omeprazole and realkalinized by coexposure to fluconazole. Vacuolar pH was alkalinized by fluconazole. Off-target effects of any medication on fungal pathogens may occur.